The best traction on a flat dry surface is provided by a flat outsole made of a rubber or other elastic material which provides good traction. Such a construction, however, provides very poor traction on a wet surface and it has been known for many years to impart various patterns of grooves and/or incisions (siping) to improve the traction of rubber soles on wet surfaces as inevitably encountered in boating.
Molded grooves permit water to flow away from the supporting surface thereby improving the traction between the surface and shoe sole. A multiplicity of incisions also provides sharp surfaces when the sole is flexed which tend to cut through the water. Currently, the most popular form of boating moccasin includes a multiplicity of incisions in the form of a triangular wave over the entire traction surface of the moccasin.